Self-locking screwing attachment devices for securing at least two parts to each other, having generally the form of a nut screwed onto a threaded tip, provided with strengthened releasable coupling means, for preventing said at least two parts from being importunately unscrewed, are known. This strengthened coupling means perform a self-locking of the coupling when screwing the nut on the tip.
These known devices generally have drawbacks of several kinds:                the nut consists of several separable parts which can be lost and should be assembled according to an accurate order,        nut not adapted to parts to be assemble and/or to threaded tips having multiple shapes and not necessarily standard; the friction surfaces required for the clamping are highly dependent on the shape of parts to be assembled, resulting in an uncertain clamping efficiency according to configurations; the adaption of these known nuts sometimes requires a significant and extensive machining,        poorly optimized dimensions.        